This invention relates to arrangements for providing deflection correction waveforms for kinescopes.
It is known that coupled multipliers may be used to provide kinescope deflection waveform S-correction for modifying the shape of substantially linearly varying deflection waveforms. S-shaping of the deflection waveform is necessary to correct the deflection scanning rate of an electron beam impinging upon the display face of a substantially flat-faced kinescope. The S-correcting waveform is typically a "third power" waveform of the substantially linearly varying deflection sawtooth waveform.
Other types of deflection waveform corrections are frequently provided to the substantially linearly varying deflection waveform to insure that the information contained in the electron beam is accurately displayed on the kinescope face. For example, it is known that to achieve deflection which is non-varying with changes in kinescope anode accelerating voltage, the deflection current waveform must vary directly with the square root of the high voltage applied to the accelerating anode of the kinescope. See, e.g., Boekhorst, A. an Stolk, J., Television Deflection Systems, Phillips Technical Library, 1962, Para. 4.1.2.
Typically, the correction necessary to achieve non-varying deflection with changes in accelerating anode voltage is provided by varying the deflection waveform directly as the sum of a constant voltage and a voltage related to the accelerating anode voltage. This is frequently achieved by charging a capacitor in the deflection waveform generator from two current sources. One source provides substantially constant current and the other provides current which varies directly with changes in the accelerating voltage. The voltage provided across the capacitor is thus corrected for changes in the accelerating voltage since the sum of a constant voltage and an accelerating voltage-related voltage is proportional to the first two terms of a Taylor's series expansion of the square root of the accelerating voltage.
However, where other deflection waveform corrections, such as S-correction, take place intermediate the accelerating anode voltage correction and the deflection winding, the final anode voltage correction will be changed by these intermediate corrections so that it will no longer provide the square root relation necessary to correct for changes in the accelerating anode voltage.